1. Field of the Invention
The present invention relates to a light emitting diode, and more particularly to a light emitting diode having enhanced radiation effect and light-emitting efficiency.
2. Description of Related Prior Art
A conventional vertical-type light emitting diode, as shown in FIG. 1, includes a frame A2 on which a bowl portion is formed for receiving a chip A1 therein. The frame A2 has two extended leads, at lower ends of which the frame A2 is soldered onto a printed circuit board A4 at soldering points A3. This type of conventional light emitting diode has relatively deep bowl portion that facilitates to enhanced light-emitting efficiency. However, it uses only one of the two leads to radiate heat and therefore has inferior radiation efficiency. It is theoretically known that the radiation effect is in proportion to the light-emitting efficiency. The poorer the radiation effect is, the poorer the light-emitting efficiency is. The vertical-type light emitting diode shown in FIG. 1 has poor radiation effect and therefore needs improvement.
FIG. 2 illustrates another conventional light emitting diode that includes a frame B2 for holding a chip B1 thereon. The frame B2 has increased width and leads having increased diameter, compared with the frame A2 shown in FIG. 1. The leads are also soldered onto a printed circuit board B4 at soldering points B3. In this type of conventional light emitting diode, the width-increased frame B2 enables a reduced overall height of the light emitting diode, and both the two leads are used to radiate heat to provide an enhanced radiating capacity. However, the frame B2 is thin in its thickness and the bowl portion on the frame B2 has a relatively small depth of about 0.4 mm that is smaller than the bowl portion on the frame A2 for the vertical-type light emitting diode of FIG. 1. Since the depth of the bowl portion also has connection with the light-emitting efficiency, there is limitation in the light-emitting efficiency of the light emitting diode of FIG. 2 and an improvement on it is desired.
It is therefore tried by the inventor to develop a light emitting diode that has relatively deep bowl portion and increased radiation and light-emitting efficiency.
A primary object of the present invention is to provide a light emitting diode that has relatively deep bowl portion and increased radiation and light-emitting efficiency. To achieve the above and other objects, the light emitting diode of the present invention includes a frame having an increased thickness to enable the bowl portion formed thereon to have a depth more than 0.6 mm to provide enhanced light-emitting efficiency. The frame also includes leads downward extended from the frame and radiating blocks provided at or close to a bottom of the frame to increase the radiation efficiency. The light emitting diode of the present invention further includes a layer of radiation-enhancing material over bottoms of the frame and the radiating blocks to enhance the radiating capacity of the light emitting diode. In the present invention, the frame and the radiating blocks or the layer of radiation-enhancing material is connected to and in direct contact with the printed circuit board to further increase the radiating area of the light emitting diode.